The present invention relates to fluid-flow control devices. The invention is particularly useful with respect to trickler or dripper nozzles commonly used in trickle irrigation, and is therefore described below with respect to that application for purposes of example only.
The many different types of dripper nozzles presently in use are generally characterized by the provision of small openings and/or circuitous paths for the water in order to cause a pressure drop so that the water exits in a slow trickle. Such nozzles, however, are costly to produce and/or are easily clogged.
My co-pending application Ser. No. 364,049 filed May 25, 1973, now U.S. Pat. No. 3,938,552 discloses a fluid-flow control device including a regulating member which is set into rapid oscillating movement to rapidly open and close an outlet passageway formed in a conduit member and thereby to control the flow of fluid therethrough. Two embodiments of the invention were disclosed in that application. In one embodiment, the conduit member was a tube formed with a radial outlet, and the regulating member was a ring enclosing the tube at its radial outlet, the ring being set in a rapid oscillating movement in a radial direction with respect to the tube to open and close its outlet. In a second described embodiment, the conduit member was formed with an axial outlet, and the regulating member was a disc which was set into rapid oscillating movement in an axial direction with respect to the conduit member to open and close its outlet.